Shaped charges adapted for use inside well casings



J. DELACOUR Sept. 2, 1958 SHAPED CHARGES ADAPTED FOR USE INSIDE WELLCASINGS Filed May 4, 1951 W him SHAPED CHARGES ADAPT ED FOR USE INSIDEWELL CASINGS Jacques Delacour, Paris, France, assignor, by mesneassignments, to Borg-Warner Corporation, Chicago, 11]., a corporation ofIllinois Application May 4, 1951, Serial No. 224,520 Claims priority,application France May 11, 1950 2 Claims. (Cl. 10220) My invention hasfor its object improvements in shaped charges adapted for use insidesoundings with a view to perforating the inner casings of the wells.

It is a known fact that the charges used at the present time includegenerally speaking in their front part a conical liner made of a metalsuch as copper or steel that closes the chamber, whether empty or filledwith material that is located to the front of the actual charge. Now, ithas been found that the perforations provided were partly closed intheir turn by a block of metal, whether copper or steel, as produced bythe melting of the metal of a part of the liner at the moment of theexplosion of the charge.

My invention has for its object to cut out this drawback. For thispurpose, it consists in locating inside the cone a cellular substancesuch as hard rubber in sponge form. Under such conditions, it has beenfound that the metal block assumes a smaller size than the blocks formedin usual practice and that it was driven home into the target withoutclosing the opening obtained by the explosion of the charge.

The single figure of accompanying drawing illustrates an embodiment ofmy invention. In said figure which is an axial vertical cross-section ofa perforator, 1 designates the cylindrical body of the perforator insidewhich are located in superposed parallel planes different hollow orshaped charges, only one of which has been illustrated.

The arrangement of the charge may be in particular of the type disclosedin the copending application, Serial No. 128,950, dated November 23,1949, now Patent No. 2,764,937, dated October 2, 1956, that has beenassigned to the Socit de Prospection Electrique, Procds Schlumberger,who is also assignor of the present application. As disclosed in thatapplication, the perforator Patented Sept. 2, 1958 1 comprises a hollowcylindrical pressure resistant housing closed at top and bottom bytightly fitting caps. The shaped charge is contained inside twoelements, to Wit: an inner frusto-conical element 2 forming the coverand the outer element 3 forming a sheath for the cover and assuming acorresponding shape. The small end of said sheath includes a cylindricalrear extension adapted to carry the priming charge 5 inside which passesthe fuse 6 that is fitted inside a slot of the sheath 3. On the otherhand, the corresponding end of the outer sheath 3 is housed inside arecess 7 provided to this purpose in the rear wall of the perforatorbody 1. The front end of the sheath 3 engages an opening 8 providedsimilarly to this purpose through the wall of the cylindrical body 1,which opening is closed by the threaded plug 9 adapted to be perforatedat the moment of the explosion of the charge, as well known per se.Lastly, 10 designates the conical liner located to the front of thecharge.

Now, according to the invention, there is provided in the concavity ofsaid liner 10, in the manner disclosed hereinabove, a mass of hardrubber or ebonite in sponge formation 12. This hard rubber or ebonite insponge formation may be replaced by any other cellular substanceassuming substantially the same physical structure.

What I claim is:

1. In well casing perforating apparatus for use in deep wells containinga column of liquid, the combination of a hollow, watertight pressureresistant container adapted to be lowered into the well and having atleast one opening formed in the side wall thereof, watertight andpressure resistant closure means for said opening, a shaped explosivecharge supported in said container and having a forward hollowed outportion facing said opening and lined with a metallic liner, and a massof hard cellular substance disposed in said container in front of saidliner for reducing the size of the metal block formed from part of thematerial of said liner when said charge is detonated.

2. Well casing perforating apparatus as defined in claim 1 in which thecellular substance comprises a mass of hard rubber in sponge form fittedin the concavity of said liner.

References Cited in the file of this patent UNITED STATES PATENTS2,494,256 Muskat Jan. 10, 1950 FOREIGN PATENTS 573,078 Great BritainNov. 6, 1945 622,062 Great Britain Apr. 26, 1949

